How/command to find out the current shell – Unix/Linux

Shell is a program that takes your commands from the keyboard and gives them to the operating system to perform. Some common types of shells are listed below:
> /bin/bash
> /bin/ksh
> /bin/csh
> /bin/sh
> /sbin/nologin
etc…

Linux Server Administrator. I'm dealing with Linux servers since 2012. I started this blog to share and discuss my ideas with the world. Check My Profile!! in uPwork (oDesk) and let me know if you need any assistance. Thanks!!